diff options
Diffstat (limited to 'drivers/watchdog/davinci_wdt.c')
| -rw-r--r-- | drivers/watchdog/davinci_wdt.c | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/drivers/watchdog/davinci_wdt.c b/drivers/watchdog/davinci_wdt.c new file mode 100644 index 000000000..cfdf8a408 --- /dev/null +++ b/drivers/watchdog/davinci_wdt.c @@ -0,0 +1,239 @@ +/* + * drivers/char/watchdog/davinci_wdt.c + * + * Watchdog driver for DaVinci DM644x/DM646x processors + * + * Copyright (C) 2006-2013 Texas Instruments. + * + * 2007 (c) MontaVista Software, Inc. This file is licensed under + * the terms of the GNU General Public License version 2. This program + * is licensed "as is" without any warranty of any kind, whether express + * or implied. + */ + +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/watchdog.h> +#include <linux/platform_device.h> +#include <linux/io.h> +#include <linux/device.h> +#include <linux/clk.h> +#include <linux/err.h> + +#define MODULE_NAME "DAVINCI-WDT: " + +#define DEFAULT_HEARTBEAT 60 +#define MAX_HEARTBEAT 600 /* really the max margin is 264/27MHz*/ + +/* Timer register set definition */ +#define PID12 (0x0) +#define EMUMGT (0x4) +#define TIM12 (0x10) +#define TIM34 (0x14) +#define PRD12 (0x18) +#define PRD34 (0x1C) +#define TCR (0x20) +#define TGCR (0x24) +#define WDTCR (0x28) + +/* TCR bit definitions */ +#define ENAMODE12_DISABLED (0 << 6) +#define ENAMODE12_ONESHOT (1 << 6) +#define ENAMODE12_PERIODIC (2 << 6) + +/* TGCR bit definitions */ +#define TIM12RS_UNRESET (1 << 0) +#define TIM34RS_UNRESET (1 << 1) +#define TIMMODE_64BIT_WDOG (2 << 2) + +/* WDTCR bit definitions */ +#define WDEN (1 << 14) +#define WDFLAG (1 << 15) +#define WDKEY_SEQ0 (0xa5c6 << 16) +#define WDKEY_SEQ1 (0xda7e << 16) + +static int heartbeat; + +/* + * struct to hold data for each WDT device + * @base - base io address of WD device + * @clk - source clock of WDT + * @wdd - hold watchdog device as is in WDT core + */ +struct davinci_wdt_device { + void __iomem *base; + struct clk *clk; + struct watchdog_device wdd; +}; + +static int davinci_wdt_start(struct watchdog_device *wdd) +{ + u32 tgcr; + u32 timer_margin; + unsigned long wdt_freq; + struct davinci_wdt_device *davinci_wdt = watchdog_get_drvdata(wdd); + + wdt_freq = clk_get_rate(davinci_wdt->clk); + + /* disable, internal clock source */ + iowrite32(0, davinci_wdt->base + TCR); + /* reset timer, set mode to 64-bit watchdog, and unreset */ + iowrite32(0, davinci_wdt->base + TGCR); + tgcr = TIMMODE_64BIT_WDOG | TIM12RS_UNRESET | TIM34RS_UNRESET; + iowrite32(tgcr, davinci_wdt->base + TGCR); + /* clear counter regs */ + iowrite32(0, davinci_wdt->base + TIM12); + iowrite32(0, davinci_wdt->base + TIM34); + /* set timeout period */ + timer_margin = (((u64)wdd->timeout * wdt_freq) & 0xffffffff); + iowrite32(timer_margin, davinci_wdt->base + PRD12); + timer_margin = (((u64)wdd->timeout * wdt_freq) >> 32); + iowrite32(timer_margin, davinci_wdt->base + PRD34); + /* enable run continuously */ + iowrite32(ENAMODE12_PERIODIC, davinci_wdt->base + TCR); + /* Once the WDT is in pre-active state write to + * TIM12, TIM34, PRD12, PRD34, TCR, TGCR, WDTCR are + * write protected (except for the WDKEY field) + */ + /* put watchdog in pre-active state */ + iowrite32(WDKEY_SEQ0 | WDEN, davinci_wdt->base + WDTCR); + /* put watchdog in active state */ + iowrite32(WDKEY_SEQ1 | WDEN, davinci_wdt->base + WDTCR); + return 0; +} + +static int davinci_wdt_ping(struct watchdog_device *wdd) +{ + struct davinci_wdt_device *davinci_wdt = watchdog_get_drvdata(wdd); + + /* put watchdog in service state */ + iowrite32(WDKEY_SEQ0, davinci_wdt->base + WDTCR); + /* put watchdog in active state */ + iowrite32(WDKEY_SEQ1, davinci_wdt->base + WDTCR); + return 0; +} + +static unsigned int davinci_wdt_get_timeleft(struct watchdog_device *wdd) +{ + u64 timer_counter; + unsigned long freq; + u32 val; + struct davinci_wdt_device *davinci_wdt = watchdog_get_drvdata(wdd); + + /* if timeout has occured then return 0 */ + val = ioread32(davinci_wdt->base + WDTCR); + if (val & WDFLAG) + return 0; + + freq = clk_get_rate(davinci_wdt->clk); + + if (!freq) + return 0; + + timer_counter = ioread32(davinci_wdt->base + TIM12); + timer_counter |= ((u64)ioread32(davinci_wdt->base + TIM34) << 32); + + do_div(timer_counter, freq); + + return wdd->timeout - timer_counter; +} + +static const struct watchdog_info davinci_wdt_info = { + .options = WDIOF_KEEPALIVEPING, + .identity = "DaVinci/Keystone Watchdog", +}; + +static const struct watchdog_ops davinci_wdt_ops = { + .owner = THIS_MODULE, + .start = davinci_wdt_start, + .stop = davinci_wdt_ping, + .ping = davinci_wdt_ping, + .get_timeleft = davinci_wdt_get_timeleft, +}; + +static int davinci_wdt_probe(struct platform_device *pdev) +{ + int ret = 0; + struct device *dev = &pdev->dev; + struct resource *wdt_mem; + struct watchdog_device *wdd; + struct davinci_wdt_device *davinci_wdt; + + davinci_wdt = devm_kzalloc(dev, sizeof(*davinci_wdt), GFP_KERNEL); + if (!davinci_wdt) + return -ENOMEM; + + davinci_wdt->clk = devm_clk_get(dev, NULL); + if (WARN_ON(IS_ERR(davinci_wdt->clk))) + return PTR_ERR(davinci_wdt->clk); + + clk_prepare_enable(davinci_wdt->clk); + + platform_set_drvdata(pdev, davinci_wdt); + + wdd = &davinci_wdt->wdd; + wdd->info = &davinci_wdt_info; + wdd->ops = &davinci_wdt_ops; + wdd->min_timeout = 1; + wdd->max_timeout = MAX_HEARTBEAT; + wdd->timeout = DEFAULT_HEARTBEAT; + + watchdog_init_timeout(wdd, heartbeat, dev); + + dev_info(dev, "heartbeat %d sec\n", wdd->timeout); + + watchdog_set_drvdata(wdd, davinci_wdt); + watchdog_set_nowayout(wdd, 1); + + wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); + davinci_wdt->base = devm_ioremap_resource(dev, wdt_mem); + if (IS_ERR(davinci_wdt->base)) + return PTR_ERR(davinci_wdt->base); + + ret = watchdog_register_device(wdd); + if (ret < 0) + dev_err(dev, "cannot register watchdog device\n"); + + return ret; +} + +static int davinci_wdt_remove(struct platform_device *pdev) +{ + struct davinci_wdt_device *davinci_wdt = platform_get_drvdata(pdev); + + watchdog_unregister_device(&davinci_wdt->wdd); + clk_disable_unprepare(davinci_wdt->clk); + + return 0; +} + +static const struct of_device_id davinci_wdt_of_match[] = { + { .compatible = "ti,davinci-wdt", }, + {}, +}; +MODULE_DEVICE_TABLE(of, davinci_wdt_of_match); + +static struct platform_driver platform_wdt_driver = { + .driver = { + .name = "davinci-wdt", + .of_match_table = davinci_wdt_of_match, + }, + .probe = davinci_wdt_probe, + .remove = davinci_wdt_remove, +}; + +module_platform_driver(platform_wdt_driver); + +MODULE_AUTHOR("Texas Instruments"); +MODULE_DESCRIPTION("DaVinci Watchdog Driver"); + +module_param(heartbeat, int, 0); +MODULE_PARM_DESC(heartbeat, + "Watchdog heartbeat period in seconds from 1 to " + __MODULE_STRING(MAX_HEARTBEAT) ", default " + __MODULE_STRING(DEFAULT_HEARTBEAT)); + +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:davinci-wdt"); 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